Physical quantity sensor and electronic apparatus

• US 9,157,927 B2
• Filed: 04/14/2014
• Issued: 10/13/2015
• Est. Priority Date: 05/28/2010
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Kanemoto, Kei
• Primary Examiner(s): Nguyen, Tung X
• Assistant Examiner(s): ALLGOOD, ALESA M
• Application Number:
  US14/252,023
• Publication Number:
  US 20140224017A1
• Time in Patent Office: 547 Days
• Field of Search: 324/162, 735/143.2
• US Class Current: 1/1
• CPC Class Codes: G01P 15/02 by making use of inertia forces using solid seismic massesG01P15/14 takes precedence
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G01P 2015/0831 the mass being of the paddle type having the pivot axis between the longitudinal ends of the mass, e.g. see-saw configuration

Abstract

A physical quantity sensor includes a first rocking body and a second rocking body. Each of the rocking bodies is supported on a substrate by a first supporting portion and a second supporting portion. The first rocking body is partitioned into a first region and a second region by a first axis (supporting axis) when viewed in plane, and the second rocking body is partitioned into a third region and a fourth region by a second axis (supporting axis) when viewed in plane. The mass of the second region is larger than the mass of the first region, and the mass of the third region is larger than the mass of the fourth region. An arranged direction of the first region and the second region is the same as an arranged direction of the third region and the fourth region.

Claims

1. A physical quantity sensor comprising:

a rocking body supported by a first supporting portion and a second supporting portion which are disposed on a first axis, and partitioned into a first region and a second region by the first axis when viewed in plan, where each of the first and second regions is provided with a movable electrode; and

fixed electrodes facing the movable electrode,

wherein the mass of the second region is larger than the mass of the first region, and

wherein the rocking body includes;

an opening portion;

a moveable weight portion disposed at the opening portion;

a connection portion connecting the movable weight portion to the rocking body;

a first arm shaped electrode portion provided toward the movable weight portion from the rocking body; and

a second arm shaped electrode portion provided toward the rocking body from the movable weight portion and facing the first arm shaped electrode portion.

2. The physical quantity sensor according to claim 1, wherein the first arm shaped electrode portion and the second arm shaped electrode portion are respectively provided in the first region and the second region.

3. The physical quantity sensor according to claim 1, wherein the first arm shaped electrode portion and the second arm shaped electrode portion are provided in a direction at least one of parallel to the first axis and the intersect to the first axis.

4. The physical quantity sensor according to claim 1, wherein the first axis is parallel to a line passing through a center of the rocking body.

5. The physical quantity sensor according to claim 1, wherein the fixed electrodes include a first fixed electrode facing the first region, and a second fixed electrode facing the second region.

6. The physical quantity sensor according to claim 1, wherein the movable electrode is commonly provided to extend over the first region and the second region.

7. The physical quantity sensor according to claim 1, wherein the first and the second supporting portions are formed using a torsion spring.

8. A motion sensor comprising the physical quantity sensor according to claim 1.